Method and apparatus for controlling the temperature of a container end portion during manufacture

ABSTRACT

Disclosed is a method and apparatus for controlling the temperature of a container end portion during manufacture, said container being filled with a product 11, and comprising a substantially tubular body portion 10 of thin-walled plastic or laminated plastic material and a butt-weldable end-piece 13 at each end of the body portion, whereby a first end-piece is fitted to one end of the body portion and the product 11 is introduced into the container via the open end of the body portion, a second end-piece 13 is introduced into the said open body portion end to an intermediate position where it partially projects into the body portion 10, and the plastic material of the body portion end region and the second end-piece is softened through application of heat energy, characterized in that the end-piece 13, by means of relative displacement between it and the body portion 10, is pressed in to the body portion to its terminal position whilst cooling gas is supplied to the transverse wall 15 of the end-piece 13.

TECHNICAL FIELD

The present invention relates to a method and apparatus for controllingthe temperature of a container end portion during manufacture.

BACKGROUND

Tubes and bottles made from thin-walled plastic or plastic laminatedmaterial are used for packaging of, for example, creams, ointments andvarious other viscous chemical/engineering preparations. Swedish PatentApplication 8800548-3 describes an end-piece and a method formanufacturing tubes or bottles by butt-welding an end-piece in both endsof a tubular-shaped body portion of thin-walled plastic or laminatedplastic material.

The advantage of manufacturing tubes or bottles in this way is that theneed to transport bulky empty containers over long distances is avoided.Accordingly the method allows the private packager to produce his owntubes or bottles without comprehensive equipment.

The tube or bottle produced according to the above method can be filledwith its product via its opening, after which a cap is affixed over theopening with the aid of, for example, screw threads.

In many cases, however, it is desirable to provide a container which hasbeen sealed in a controlled environment so that the customer can confirmthat the packaging is unopened. This results in enhanced quality, bothfor the packaging and its contents.

During production of such a sealed container it is advantageous thatfilling with the product occurs between the fitting of the firstend-piece, preferably tubularly formed, and the second end-piece.

In the method according to said Swedish Patent Application 8800548.3tubular-shaped body portions are located on a rotary indexing table formovement between various stations. At one station each end-piece isintroduced into the upper end of a corresponding body portion by apiston to an intermediate position where it partially projects into thebody portion. This partially assembled work piece is then moved to thenext station where heating energy is supplied to the circumferential endregion of the tube and intersecting region of the end piece. Once atemperature is attained at which the material is sufficiently soft, thework piece is advanced to the subsequent station where a piston isreapplied to push the end piece to its terminal position. Rapid coolingof the welding site is then achieved by means of passages within thepiston for a cooling fluid.

SUMMARY OF THE INVENTION

Up until now it has proved impossible to apply the end-piece with thepiston in situ during heating since the rim of the end-piece upon whichthe piston acts is subjected to heating to between 300° C.-500° C.,thereby softening the material and causing it to adhere to the piston.

The object of the present invention is thus to provide a method and anapparatus which permits the production of filled containers at a highrate whilst avoiding the above-mentioned problem.

This object is achieved according to the invention by a method formanufacturing a container by sealing an end-piece having a transversewall portion and a peripheral portion to an open end portion of thecontainer, the method comprising the steps of:

introducing the end-piece into the open end portion of the container toan intermediate position such that the end-piece partially projects intothe open end portion;

heating the open end portion and the peripheral portion of the end-pieceso as to soften the open end portion and the peripheral portion, and

displacing the transverse wall portion of the end-piece to its terminalposition relative to the open end portion while simultaneously coolingthe transverse wall portion of the container.

The present invention also provides an apparatus for manufacturing acontainer by sealing an end-piece having a transverse wall and aperipheral portion to an open end portion of the container, comprising:

displacement means for displacing the transverse wall of the end-pieceinto the open end portion of the container to an intermediate positionrelative to the open end portion;

heating means for heating the open end portion and the peripheralportion of the end piece so as to soften the open end portion and theperipheral portion; and

cooling means for cooling the transverse wall while simultaneouslydisplacing the transverse wall of the end-piece to its terminal positionrelative to the open end portion.

Preferred methods and embodiments of the apparatus according to theinvention are given in the respective dependent claims.

Since, according to the invention, the abutment means acts on thetransverse wall of the end-piece which is not subjected to directheating, and cooling gas is supplied thereto, there is no tendency forthe abutment means to adhere to the end-piece.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, withreference to the drawings in which

FIGS. 1 and 2 schematically show the application of an end-piece to atubular body portion in two steps with apparatus according to theinvention, and

FIG. 3 shows the compression of the weld-seam.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The flattenable tubular body portion 10 shown in the drawings can bemade from a single-layer plastic material or from a laminate comprisinga metal foil which provides the body portion with better barrierproperties. The body portion can be produced by a foil butt-seam welderor, alternatively, from an extruded tube, cut to the appropriate length.Such body portions normally have a wall thickness well under 1 mm.

In the drawings only the upper end of the body portion is shown. Thelower part of the body portion is already fitted with an end-piece inthe form of, for example, a discharge outlet with cooperating screw cap.The body portion is filled via its open end with a product 11 to apredetermined level which corresponds to the desired quantity for thecontainer. The body portion is now placed vertically with the openingupwards in a cylindrical holder 12 in a (not shown) rotary indexingtable which is provided with means for fitting the end-piece in thefollowing sequence of steps.

In FIG. 1 the end-piece 13 has been partially introduced into theupwardly open body portion end and then advanced one stage to thewelding station shown in FIGS. 1 and 2.

The end-piece 13 comprises an insert section 14 which, on the inner end,is provided with a transverse wall 15 and, on the other end, is providedby a U-shaped section 16. The insert section 14 tapers inwardly towardsthe transverse wall 15. The U-shaped section is provided with a groovethat tapers towards the bottom of the U-shaped section.

The end-piece can, by way of example, be produce by injection-molding,whereby a barrier foil blank may be included on the inner side or theouter side of the transverse wall 15.

The welding station is provided with passages 17 for supplying hot gasvia directed openings to the region of the body portion end edge and tothe groove in the U-shaped section 16 in order to soften these regionsby application of heat to a temperature between about 300°-500° C. Aftersuitable heating, the holder 12 is displaced upwardly in the weldingapparatus so that the end-piece 13 is pressed into the tubular bodyportion until the rim of the body portion meets with the bottom of thegroove, as shown in FIG. 2. A central bell-shaped nozzle head 18 ofslightly smaller diameter than the transverse wall 15 serves as anabutment for the endpiece 13.

The nozzle head 18 is formed with a substantially flat undersideprovided with a central recess 19 and a groove 23 which extendscircumferentially above the perimeter of the transverse wall 15. Asubstantially vertical branch conduit 24 for the supply cooling gasopens into the groove 23 and accordingly distributes cooling gas aroundthe perimeter of the transverse wall 15.

A suitable cooling gas can be cold air. Expended cold air flows from thegroove 23 via the underside of the nozzle head to the surrounding space22 from where the utilized cold air and hot gas is drawn from thewelding station via passages 25. In this way the temperature of thetransverse wall region which is abutted by the nozzle head is controlledthereby preventing adhesion of the nozzle head thereto. Advantageouslythe underside of the nozzle head may be coated with a "non-stick"material, such as TEFLON.

FIG. 3 shows the subsequent step of compressing the U-shaped section 16whilst still soft so that a seal in this region is achieved. Compressioncan be carried out by a vertically displaceable abutment 26 and aplurality of horizontal compression devices 27. These compressiondevices may be mechanically or elastic-hydraulically operable.

The invention is not restricted to the above described embodiments, butmay be modified within the scope of the appended claims.

I claim:
 1. A method for manufacturing a container by sealing anend-piece having a transverse wall portion and a peripheral portion toan open end portion of said container, said method comprising the stepsof:introducing said end-piece into said open end portion of saidcontainer to an intermediate position such that said end-piece partiallyprojects into said open end portion; heating said open end portion andsaid peripheral portion of said end-piece so as to soften said open endportion and said peripheral portion; and displacing said transverse wallportion of said end-piece to its terminal position relative to said openend portion while simultaneously cooling said transverse wall portion ofsaid container.
 2. A method according to claim 1, where said end-piececomprising a first end piece, and said open end portion of saidcontainer comprises a first end portion of said container, and includingthe step of fitting a second end-piece having a discharge outlet ontosaid second end portion of said container.
 3. A method according toclaim 1, further comprising the step of supplying a product to saidcontainer through said open end portion.
 4. A method according to claim1, wherein said heating step comprises supplying hot gas to said openend portion and said peripheral portion of said end piece.
 5. A methodaccording to claim 1, wherein said simultaneously cooling comprisessupplying a cooling gas to said transverse wall portion of saidcontainer.
 6. A method according to claim 4, further comprising removingsaid hot gas.
 7. A method according to claim 5, further comprisingremoving said cooling gas.
 8. A method according to claim 1, furthercomprising sealing said peripheral portion of said end-piece to saidopen end portion of said container.
 9. Apparatus for manufacturing acontainer by sealing an end-piece having a transverse wall and aperipheral portion to an open end portion of said container,comprising:displacement means for displacing said transverse wall ofsaid end-piece into said open end portion of said container to anintermediate position relative to said open end portion; heating meansfor heating said open end portion and said peripheral portion of saidend piece so as to soften said open end portion and said peripheralportion; and cooling means for cooling said transverse wall whilesimultaneously displacing said transverse wall of said end-piece to itsterminal position relative to said open end portion.
 10. An apparatusaccording to claim 9, wherein said cooling means comprises asubstantially vertical conduit and a nozzle-head having a diameterslightly smaller than the diameter of said transverse wall, said nozzlehead containing a circumferential slot which opens into a ring-shapedgroove circumscribing the perimeter of said transverse wall, and furtherwherein said substantially vertical conduit, said circumferential slotand said ring-shaped groove being in fluid connection with each other.11. An apparatus according to claim 9, further comprising suction meansfor removing gases from the area of said transverse wall.
 12. Anapparatus according to claim 9, further comprising sealing means forsealing said peripheral portion of said end-piece with said open endportion of said container.